26 ANNALS OF SCOTTISH NATURAL HISTORY 



surface of the stone before the latter half of March. The earliest 

 date on which I have found a female in her nest is February 14 in 

 Dumbartonshire, but from March 10 onwards I have found them 

 commonly. 



Inside this nest the female remains till her young are fully 

 developed and ready to forage for themselves. The eggs, twenty to 

 thirty in number, are produced normally about the middle of March, 

 and appear at first as a small white mass attached to the genital 

 aperture on the under side of the hind-body ; this white spot 

 gradually expands, till, after the middle of May, it envelops the 

 whole hind-body with the exception of the upper surface, and the 

 creature is then embedded in the swollen embryonic mass, which 

 projects below, behind, and round the sides of the hind-body, and 

 forms a margin equal in breadth to the cross diameter of the hind- 

 body itself. At the beginning of June the tiny white youngsters 

 attached to the female can be distinctly made out, and by the 

 middle of June they are ready to give up that attachment to their 

 parent which has been maintained throughout the entire develop- 

 ment from the egg to the perfect False-scorpion, and to go forth 

 from the nest on a free life. The earliest date on which I have 

 seen the young moving free is May 25, at Castlecary. 



A note on the adult and young from my West Lothian note- 

 book, June 25, 1901, may be of interest here. "Nests of O. mus- 

 corum were fairly common on a rocky patch by the wayside near 

 Preston House, but they were for the most part empty and generally 

 wasted, as if to indicate that they were no longer required. Even- 

 tually one with an opening in it proved to contain young. The 

 little creatures, a dozen or so in number, were venturing forth from 

 their retreat, and as they wandered among the tiny cracks and 

 crevices of the stone, they went through the antics of the adult 

 perfectly. In moving about they held their pincers well forward, 

 and kept opening and shutting them ; and even when there was 

 nothing to cause any suspicion, they would suddenly dart backwards 

 in the manner so characteristic of this group of creatures, as if an 

 enemy lurked in a part of the stone they had touched. They ran 

 backwards rapidly, and far too, considering their size. They were 

 very light in colour, with a greenish hue most pronounced on the 

 carapace and with a pinkish tinge on the pincers. The adult was 

 not to be seen, being probably out on a hunt for food. I found other 

 nests closed, which contained the adult and her young. The young 

 of one of these nests, on its being opened, soon shewed that they 

 were ready for active life, as one after another came forth to enjoy 

 its new freedom, and seemed to be intent on wandering away 

 without any intention of returning. One brood consisted of twenty- 

 four individuals." 



At the beginning of July Obisium muscorum is again laying, but 



